The forward-chaining production system is a computational model for bottom-up computation. Production systems are often used for developing expert systems or when modeling the human brain in artificial intelligence or cognitive sciences [New 72]. There are many programming languages for developing forward-chaining production systems, such as OPS5 or OPS83, which are developed by Charles Forgy at Carnegie Mellon University.
There are also production systems that are called backward-chaining production systems. The backward-chaining production system is a computational model for top-down computation. Forward- and backward-chaining production systems are called such because they are also models of forward and backward inferences.